selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/include/rdma/ib_sysfs.h b/include/rdma/ib_sysfs.h
new file mode 100644
index 000000000..3b77cfd74
--- /dev/null
+++ b/include/rdma/ib_sysfs.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
+/*
+ * Copyright (c) 2021 Mellanox Technologies Ltd.  All rights reserved.
+ */
+#ifndef DEF_RDMA_IB_SYSFS_H
+#define DEF_RDMA_IB_SYSFS_H
+
+#include <linux/sysfs.h>
+
+struct ib_device;
+
+struct ib_port_attribute {
+	struct attribute attr;
+	ssize_t (*show)(struct ib_device *ibdev, u32 port_num,
+			struct ib_port_attribute *attr, char *buf);
+	ssize_t (*store)(struct ib_device *ibdev, u32 port_num,
+			 struct ib_port_attribute *attr, const char *buf,
+			 size_t count);
+};
+
+#define IB_PORT_ATTR_RW(_name)                                                 \
+	struct ib_port_attribute ib_port_attr_##_name = __ATTR_RW(_name)
+
+#define IB_PORT_ATTR_ADMIN_RW(_name)                                           \
+	struct ib_port_attribute ib_port_attr_##_name =                        \
+		__ATTR_RW_MODE(_name, 0600)
+
+#define IB_PORT_ATTR_RO(_name)                                                 \
+	struct ib_port_attribute ib_port_attr_##_name = __ATTR_RO(_name)
+
+#define IB_PORT_ATTR_WO(_name)                                                 \
+	struct ib_port_attribute ib_port_attr_##_name = __ATTR_WO(_name)
+
+struct ib_device *ib_port_sysfs_get_ibdev_kobj(struct kobject *kobj,
+					       u32 *port_num);
+
+#endif